Sand cores are typically produced in core boxes comprising a cope or top portion, a drag or lower portion and one or more cavities formed therebetween. An injection tube or extruding tube is inserted into a passage in the cope to inject core sand into the cavity. In the cold box method of forming sand cores, the core sand is mixed with resin and the cores are hardened by introducing catalyst into the core box.
In conventional cold box core making machines, catalyst is introduced into the core box after sand injection by removing the injection tube from the core box, transferring the core box by a transfer mechanism to a second location where the gassing plate is located, and placing the gassing plate onto the cope. The gassing plate extends into the passage in the cope when in the gassing position and passes catalyst into the cavity to harden the core or cores therein. Alternatively, the catalyst injection apparatus, such as the gassing plate, may be transferred to the core box prior to the placing of gassing plate onto the cope.
Conventional apparatus for gassing of cores has a number of disadvantages. The step of removing the injection tube from the core box to clear the cope passage for the gassing plate is time consuming. A further disadvantage is the necessity of transferring the core box or catalyst injection apparatus prior to introducing catalyst into the core box. Depending upon the size and complexity of the machine and core box, the cost of the transfer mechanism could account for several thousand dollars. Further, the machine cycle time is increased by 3 to 10 seconds for the transfer motion. Also time consuming is the step of placing the gassing plate upon the cope and pressing the gassing plate against the cope prior to gassing. The steps of removing the injection tube from the core box, transferring either the core box or the catalyst injection apparatus, and placing a gassing plate upon the cope are particularly time consuming because those steps are performed during each production cycle. Moreover, the gassing plates are an added expense.